【作者】 孙兴福；

【导师】 霍丹群；

【作者基本信息】 重庆大学 ， 生物医学工程， 2005， 硕士

【摘要】 生物法处理低浓度废气以其处理效果好,投资运行费用低,无二次污染等优点成为当今世界的前沿热点课题之一。在国外,已有相当数量的实际工业装置投入运行,而在我国目前还主要处于研究阶段,只有少数有关应用方面的报道。目前针对VOC 废气处理的生物过滤塔实验研究已作了一些工作,对生物膜滴滤塔的研究工作也有相关报道,理论研究却还有限。在已有的理论研究中,绝大多数理论模型的理论基础都是吸收-生物膜理论,该理论认为VOCs 是通过扩散效应、平流效应以及气相、液/固相的传递而被吸收到液/固相中,进而通过微生物降解生成CO2, H2O 和生物机体。但是,在挥发性有机废气的生物净化处理过程中,通常生物膜填料塔都是用水来润湿生物膜的,由于这些有机废气几乎不溶于水或仅仅微溶于水,因此用吸收-生物膜理论不能很好的解释它们依靠扩散(浓度梯度为推动力),通过液膜,而后到达生物膜,并被其中的微生物捕获的净化过程机理。而且整个过程由于涉及了液膜扩散、多元多相流动、生化反应技术变化以及过渡区等复杂问题,所以模型计算的难度非常大,计算的准确性也比较低。本文以VOCs 中比较常见的甲苯作为研究对象,研究了本实验室驯化筛选的菌种的生长和降解特性;在此基础上,依据酶的抑制机理建立了在静态条件下甲苯的有抑制降解动力学;并以静态的降解模型为基础,依据生物滴滤塔内的吸附-生物膜理论建立了有抑制的甲苯降解动力学。通过本文的研究工作,得到以下主要结论: 1.本实验室最佳降解条件为:pH=7,温度为30-40℃,接种量为5%。在一定的甲苯浓度范围内,随着甲苯浓度的增大,比生长速率和比降解速率也增大,当增加到一定程度后,继续增加甲苯浓度,比生长速率和比降解速率反而下降。2.在静态条件下,通过甲苯浓度对甲苯比降解速率影响的实验,结果显示,当甲苯浓度在0-300mg/L 范围内时,比降解速率随甲苯浓度的增大而迅速增加,在300mg/L 达到0.0735h-1,在此之前表现为底物的无抑制状态。当甲苯浓度大于320mg/L 时,比降解速率开始呈现非线性下降,在780mg/L 浓度下的比降解速率降至0.0479h-1。以此为基础,依据酶的抑制机理建立了有抑制时甲苯降解菌的生长模型和甲苯降解模型。降解模型方程为: q=3.8681(C_s/774.121+C_s)(1(1+C_s/80.135))更多还原

【Abstract】 The biological treatment technology of VOC waste gas has become a research hotspot in the world because of high purification efficiency, low charge of investment and run, and no secondary pollution etc. Up to now, many practical installations have been used in the West Europe, while there are only a few reports about its application in our country. Nowadays, a few experimental rearch of trickling biofilter treatment technology of VOCs waste gas have been carried out, there were a few related reports about trickling biofilter too, but the theoretical rearch was still within limits quite too. Within the reports about theoretical rearch in nowadays, a large per cent of theoretical bases of kinetic model were absorption biofilm theories. It is consider that VOCs was absorbed in liquidum-soild through diffuseness action and the carries gas and liquidum-soild. Furthermore, VOCs was resolved into CO2, H2O and orgnism. So, the working-out of kinetic model equation was became very complex and the accuracy was became very bad. This work was process based on the follow research: the microorganism is cultivated and domesticated. A visual experiment apparatus is designed and made firstly and then the two-phase flow friction characteristic and purification of toluene are studied visually. From the viewpoint of mass and heat transfer in engineering thermophysics, combined with biochemical reaction kinetics considering the limitation of oxygen, a new capillary model has been proposed to study the degradation characteristic of trickling biofilter. Based on the process of biodegradation mechanism of trickling biofilter and the Adsorption-Biofilm theory, a Kinetic model of Toluene biodegradation was set up. The important conclusions are drawn in the follows: 1.By escalate toluene concentration, a bacteria which had the ability to degradate toluene as a sole carbon source was screened and breeded from active sludge of Chongqing steel coking factory. The strain was further identified as Pseudomonas sp, whose best growth conditions was set as follows: the temperature was 35℃, pH=7, the first toluene added quantity was 20ul, the inoculate quantity was 5%. The best degradation conditions is: the temperature was 30-40℃, pH=7 and the inoculate quantity was 5%. 2.In laboratory conditions, from the experiment of degradation rate under different toluene concentration, it is found that with the increase of the toluene concentration of less than 300mg/L, the toluene degradation rate increase too, furthermore, the toluene degradation rate increase to 0.0735h-1 when the toluene concentration was 300mg/L. On the contrary, with the increase of the toluene concentration of more than 320mg/L, the toluene degradation rate was decreased nonlinerity, the toluene degradation rate decreased to 0.0479h-1 when the toluene concentration was 780mg/L. Based on the above experiment conclusion and the restraning mechanism of enzyme, a Kinetic model of the train Growth and Toluene biodegradation was set up under the restraning condition. The model equation is the follow: 3.8681774.121 1 80.135SS SqC= + C ×+ C The model equation is the follow: 0.2841237.3 1 238.1SS SuC= + C ×+ C.From the studying for model equation, it was found that a good pertinence was showed between calculated data and test data. 3. From the experiment of trickling biofilter treatment VOCs, several important conclsion was draw that with the increase of the gas flow rate, liquid flow rate, and the inlet toluene concentration, the purification efficiency decreases. 4. Based on the Kinetic model of laboratory conditions, combined with the Adsorption-Biofilm theory, a Kinetic model of Toluene biodegradation in trickling biofilter was set up. The model equation is the follow: ( ) ( )( )( )( )211110.1137640 7.75 0.122 121985.7 0.107 12163.8 1475.1 12163.8 550.6 121nn n nnnndCC C h P Qh Cdh Q P Qh CP Qh CP Qh C= ? ×+?? + + ? +×+??×???? ++ ?? ++???? From the compare of cell concentration value from experiment and formula calculation, it is found that the model equation was accord.更多还原